This U01 Translational Research in iVluscular Dystrophy will support the deveiopment of recombinant human biglycan (rhBGN) as a therapeutic and to prepare the data package necessary for an IND filing with the FDA. It builds upon work supported by an exploratory R21 proposal to our laboratory where we have demonstrated that systemically-delivered, rhBGN counters the dystrophic phenotype in mdx mice and improves muscle function. Notably, rhBGN is effective when delivered at 3 week intervals and at doses of <10mg/kg. We propose a 4 year development plan to produce and to validate rhBGN material that is compatible with use in clinical trials. This plan will extend from pilot studies with material produced by transient transfection, to PK/PD in the mdx mouse model, to dose optimization with highly characterized material produced from a stable cell line under cGMP conditions. To maximize the efficiency and speed of this process, the work will make use of standardized models and assays as well as collaborations with several expert vendors of biologic development services. We have also enlisted consultants who have extensive expertise in the manufacturing, testing and regulatory issues that are unique to biologies.